• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.798-803
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• 2023

In the industrial internet of things (IIoT) industry, including smart factories, there are many cases where electronic devices are complexly combined and installed due to the recent development of intelligent information technology. Electromagnetic waves generated from such complex facilities affect other devices and services, which can lead to safety issues. The problem such as electromagnetic interference (EMI) and electromagnetic compatibility (EMC) generated when controlling complex facilities is an essential element that must be solved, and the engineering basis for EMI and EMC must be established to foster the industry of complex facilities. Therefore, in this study, EMC & EMI engineering demonstration cases for solar power fixed facilities using the national standard guideline have been analyzed. The results show that the electromagnetic risk indices in the solar power facilities have been degraded up to control level, and a national EMC engineering system has been proposed for complex facilities.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.533-540
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• 2008

In the sum and difference pattern synthesis problem of the equi-spaced monopulse tracking linear array antennas, an efficient numerical approach to deriving the relative excitation current weights of antenna elements is presented for the desired patterns. This method is based on the optimum perturbation of null points which are inherent to the Schelkunoffs polynomial representing the pattern array factor. Accordingly, opposite to the conventional method in which the excitation weights are directly optimized, this method is advantageous in that the patterns with the desired individual sidelobe levels(SLLs) and the corresponding excitation weights are easily synthesized by the control of null points. Furthermore, it is showed that two types of difference patterns can be synthesized as imposing the different initial values of null points in the optimization process. The proposed method is numerically validated by synthesizing the patterns with the arbitrary SLLs and substituting the extracted results into the array factor equation.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.1
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• pp.20-27
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• 1992

A synthesized isotropic pattern antenna can be realized by arrangeing $\lambda$/ 2 dipole along each x, y, z axis. The sleeve type $\lambda$/ 2 dipole antenna is used as a basic element for a proper impedance matching at feeding point and minimum mutual coupling effect between each element at 820 MHz - 895 MHz band. The total electric field intensity radiated from the designed isotropic pattern antenna is drived from the magnetic vector potential which is produced by each sleeve $\lambda$/ 2 dipole in the far field. This total electric field intensity is inversely proportional only to distance $\gamma$from the origin of coordinates, and pattern factor variation is less than 2.1dB. The measured value of total electric field variation depending on pattern factor is less then 2.8dB, and the difference between the calculated and measured value is 0.7dB.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.1
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• pp.57-66
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• 1997

1950년대 이래로 주로 군에서 발달되어 온 원격 탐사용 레이다에는 여러 종류가 있지만 주로 SLAR(Sidelooking Airborne Radar), SAR(Synthetic Aperture Radar), Scatterometer, Alti- meter 등이 많이 사용된다. SLAR와 SAR는 주로 넓은 지역의 레이다 영상을 얻는데 사용되기 때문에 영상 레이다라고 일반적 으로 분류된다. SLAR에서는 안테나 빔폭에 의해 분해능이 결정되기 때문에 원거리(특히 인공위성) 에서는 사용하기 곤란하다. SAR는 거대한 안테나를 시간적으로 합성해서 분해능을 향상시키는 방 식이므로 기본적으로 방대한 양의 데이타를 처리해야 하는데, 분해능을 좋게 할수록 필요한 신호 처리의 양은 기하급수적으로 증가한다. SAR의 기본 구성품은 일반적인 레이다와 크게 다를 바 없 으며, 단지 아주 작은 분해능을 실시간으로 요구할 때에는 막대한 계산량으로 인한 신호처리에서 의 병목현상을 적절히 처리하는 것이 중요한 연구 테마가 되고 있다.

• Electronics and Telecommunications Trends
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• v.33 no.3
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• pp.41-50
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• 2018

In order to ensure the electromagnetic safety of a complex facility equipped with a variety of electric and electronic equipment, the European Union (EU) has enacted and applied the Electromagnetic Compatibility Directive (EMC Directive 2004/108/EC) to a fixed installation. This paper introduces the regulations and techniques related with electromagnetic compatibility (EMC) engineering applied to a fixed installation, which is used to prevent a malfunction of critical equipment and systems caused by unwanted electromagnetic waves and to operate the facilities with stability.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.5
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• pp.442-451
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• 1997

We described a miniaturization of microstrip filters by the exact synthesis. With the exact synthesis, we can design completely new circuits physically realizable. The complex procedure for the network synthesis could be reduced by using computer software. It is a new design procedure ensuring the creation of optimum networks which have minimum number of elements. The exact synthesis gives more possibilities to make wideband filters which require bandwidth of 50~100 %. S-plane Bandpass prototypes are made with non-redundant filter synthesis technique that has transmission zero locations at required frequencies. Because this method uses the transmission lines which lengths are ${\lambda}$/4 at the stopband center frequency, we can reduce the size of the filter dramatically.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.67-76
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• 2006

This paper describes the analysis method to define the system specification for conducted EMI environment and verification method to evaluate the conducted EMI performance. Conducted EMI environment is characterized by the electrical power subsystem which is mainly issued by the switching circuit noise, common ground impedance coupling. To define and control these EMI problems, EMI assesment through system analysis are preceded at the early design phase and then EMI reduction methods are applied during the unit/system development phase. System EMC should be carefully controlled and designed in the consideration of EMC safety margin and its performance is fully evaluated at the whole development period.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.4
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• pp.448-458
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• 2013

In this paper, we present the performance and the experimental results of the adaptive beamformer in the radar system with the planar active array. The study of the adaptive beamformer has already been performed in several literatures, but it is difficult to find the results or examples those are implemented in the actual radar system. Here we employ the adaptive beamformer to the practical radar system with subarray architecture. The performance of beamformer will be demonstrated by modeling and simulation and finally the far-field experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.333-341
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• 2015

In this paper, a 0.5~4 GHz frequency synthesizer having good phase noise performance is proposed. Wideband output frequencies of the synthesizer were synthesized using DDS(Direct Digital Synthesizer) and analog direct frequency synthesis technology in order to obtain fast settling time. Also in order to get good phase noise performance, 2.4 GHz DDS clock was generated by VCO(Voltage Controlled Oscillator) which was locked by the 100 MHz reference oscillator using SPD(Sample Phase Detector). The phase noise performance of wideband frequency synthesizer was estimated and the results were compared with the measured ones. The measured phase noise of the frequency synthesizer was less then -121 dBc @ 100 kHz at 4 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.291-301
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• 1999

A method for the synthesis of one-dimensional nonlinear distribution function is presented for the desired inverse scattering pattern. This method is based on the inverse transform of the solution of the Riccati equation derived from one-dimensional inverse scattering problem. Since the solution is analogous to the array factor or normalized space factor in collinear array antenna, the synthesis method for field pattern is applied for the construction of the involved line-source nonlinear distribution function. The suggested method is carried out under the optimization process, and is numerically verified by synthesizing the dispersive transmission line profile within the specified frequency band and control of scattered field on resistive strip.